Last Home Server

There is something wrong with the dimensions of the gezebo at spawn. I can't for the life of me figure out what the heck I did wrong!
I'll try and explain as best I can:

The eastern half of the gazebo does not align properly with the north and south sides of the gazebo. If you take a close look at the NorthWest side, eight sandstone blocks align diagonally to the small arches  and is perfect! Wheres on the NorthEast side, 7 sandstone blocks align, which is NOT perfect! I can't figure out what's wrong!(look at attachment) If someone can see what the problem is and figures out how to fix it, I would be very much obliged if they were to do so! Hopefully I explained it well enough lol!